About the dust, if it's not done already try to check well and not just the dust that you can see directly when you open the PC unit. Few days ago I got the GPU off because it was always overheating and very noisy, reached 90°c without gaming, and I saw there was a block of 2cm of dust in it, the fan was absolutely useless as the dust blocked the air from it, and it was turning faster for nothing.
But those mail spams sure aren't any dust...